Chronic obstructive pulmonary disease (COPD) is a type of obstructive lung disease characterized by persistent airflow limitation. It is preventable, treatable but progressive and associated with co-morbidities. According to WHO, COPD presently is the third leading cause of death in the world and is expected to rank second by 2020. Aquaporin 5 (AQP5) is a membrane channel protein playing an important role in fluid secretion, altered regulation of which results in pulmonary diseases. AQP5 gene is located on chromosome 12q13 and the single nucleotide polymorphism (SNP) rs146762965 lies in the coding region corresponding to the secondary structure of channel protein. Our objective was to evaluate the association of this polymorphism with COPD in north Indian population. Genotyping was successfully done in controls and cases (100 each) by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). PCR products were digested with restriction enzyme (FauI) and analyzed on 12% polyacrylamide gel (PAGE). Allele and genotype frequencies in both the groups were compared statistically by SPSS (v21.0). Genotypic frequency showed 19% CC and 81% CT in patients, while 42% CC and 58% CT in controls. The allelic frequency showed 71% of ‘C’ allele in controls as compared to 59.5% in patients. The ‘T’ allele was 29% in controls and 40.5% in cases. Due to the higher frequencies of ‘CT’ genotype in COPD cases, there is a significant association (P<0.01) with the disease. The ‘T’ of rs146762965 polymorphism may be the risk allele for COPD in the North Indian population.
